This application claims the priority of European Patent Application No. 01810809.2 filed on Aug. 21, 2001, the disclosure of which is being incorporated herein by reference.
The invention relates to a delivery device for removing folded printed products, which are transported straddling with the aid of circulating carriers on the saddle-shaped support of a conveying arrangement. The delivery device is provided with a gripping device for gripping the printed products, such that they can be transported away with the conveying arrangement.
Delivery devices of the aforementioned type have long been known in the print-processing industry and, in particular, are used to carefully lift off printed products such as brochures, newspapers and the like from a gathering section moving in longitudinal direction. The printed products lifted off the gathering section are deflected and are supplied, for example, to a device for trimming the top, bottom and front.
In particular, the gathering section has an endless gathering chain on which feeders deposit printed sheets that are removed from a stack for forming the printed products. Carriers are arranged evenly spaced along the gathering chain and are used to transport the folded printed sheets deposited on the chain. The carriers can be attached to the gathering chain, such that they can be adjusted for changing the spacing. For the so-called xe2x80x9cselective binding,xe2x80x9d the printed products are selectively assembled and the thickness of the printed products can be changed in this way. The assembled printed products as a rule are bound, in particular in the region of the gathering chain, with the aid of a wire-stitching machine. In that case, the gathering chain is preferably a double-gathering chain.
In the high-performance range, the production speed is frequently limited by the capacity of the delivery device, which must lift and deflect the printed products carefully and, at the same time, without interruption. Further, the separate printed products must be lifted off the conveying track at a high enough speed, so that the following printed product does not collide with the previous one. In addition, the printed products must be gripped and lifted off with enough care, so that the printed products are not damaged and, in particular, no markings are created on the outside. For the xe2x80x9cselective binding,xe2x80x9d it should furthermore be possible to remove printed products of different thickness and different formats with the same high capacity.
Swiss Patent No. CH-A-358 100 discloses an delivery device, which lifts up the printed products with a sword and then inserts the printed products between successively arranged roller pairs. The rotational axes of the respective roller pairs are directed parallel to the movement plane of the sword and perpendicular to its slanted movement components. The slanted orientation of the sword movement and the roller pairs, as well as a drive connection of the sword are dimensioned such that the printed products retain their horizontal conveying speed when they are lifted off. The printed products are deflected relatively sudden and without particular care with respect to the product. The production speed of the system is limited to 8,000 to 10,000 copies per hour, depending on the chain division and format.
A different delivery device is known from Swiss Patent No. CH-A-525 142, which is designed to permit a further increase in the speed. A lift-off sword is provided for this, which is moved along an elliptical path in such a way that the movement component above the chain apparatus is always oriented in advancing direction.
European Patent No. EP 1 072 546 A1 discloses an apparatus, comprising a star-shaped, rotatingly driven device, for removing the printed products above the gathering chain with the aid of tongue-like gripping members that lift the printed products from the gathering chain quickly and in the most stable position possible. The products are gripped by the tongue-shaped clamping members of a stationary sword and pulled in a 90xc2x0 curve onto vertically moving belts. The rotating gripping members grip the printed products with a speed that is slightly higher than the transporting speed of the gathering chain. As a result, the printed products are pulled somewhat away from the carriers and thus do not hinder the outgoing printed product. A production speed of 20,000 to 25,000 copies per hour can be achieved, depending on the chain division and the number of rotating gripping members. The disadvantage of this arrangement is the comparatively large space required for the rotating gripping members and the high gripping forces necessary for controlling the acceleration and delay forces that occur during the deflection of the printed products. In addition, difficulties can arise during the processing of individual sheets in the case of a malfunction. In that case, the gripping members must automatically adjust to the thickness of such an individual sheet during the operation, which is very involved from a design point of view. During the individual readjustment from 21xe2x80x3 to 14xe2x80x3, the number of gripping arms must furthermore be increased from two to three.
It is the object of the present invention to develop an delivery device for removing folded printed products from a support, which permits an even higher production speed while still operating carefully and in a safe manner. In addition, it should have a compact design.
This object is solved with a delivery device having a gripping device for picking up and transporting off printed products in that the gripping device is provided with at least two rotating gripping members. The rotating gripping members are respectively positioned along the circumference of a rotating carrier between which the printed products are gripped and lifted off. The printed products are gripped by the rotating gripping members, which may be respectively positioned on the rotating carrier. As a result, the movement of the printed products is not limited to a circular path or a linear path, and thus, the movement of the printed products may have an optimum design. In particular, the movement path can be designed such that the collision with a following printed product associated with known delivery device at higher production speeds is avoided. According to the invention, a speed can be achieved at which the printed products are taken over virtually without impact by the gripping members, thus assuring a careful handling of the printed products. Furthermore, the printed products may be transferred to an additional conveying arrangement, for example onto belts, with a very small impact. Since rotating arms are not required according to the invention, a particularly compact design of the delivery device and gripping members may be obtained.
If, according to another modification of the invention, the gripping members have a beehive design, a particularly high production speed with careful handling of the printed products may be achieved. The largest diameter for the beehive-shaped gripping members is preferably dimensioned such that the resulting circumferential speed per cycle is higher than the chain division of the conveying arrangement. As a result of the somewhat higher, horizontal maximum circumferential speed of the beehive-shaped gripping members, as compared to the speed of the conveying arrangement, the printed product can be withdrawn optimally from the carriers. The beehive-shaped gripping members are preferably arranged in such a way that the printed products are displaced in the direction of the decreasing diameter during the carrier rotation. The printed products are consequently braked continuously in a horizontal direction and are transferred with a minimum horizontal speed to the conveying arrangement that is positioned at a right angle thereto.
Other advantageous features follow from the dependent patent claims, the subsequent description and the drawing.